Centipede - Constraint Satisfaction Problem Solver for Go

Centipede is a Constraint Satisfaction Problem solver written in Golang. Learn more about CSPs.

There is also a very informative slide deck about CSPs available from Stanford University here.

Features

Problems are defined using sets of Variable, Constraint, and Domain. Some convenient generators have been provided for Constraint and Domain.
Variable values can be set to values of any data type in Go (using the interface{} feature). However, mixing datatypes in variables that are compared to each other is not recommended. The safest approach is to set all Variable domains to slices of the same type.
The search algorithm used in this library is an implementation of backtracking search.
The solution of many complex problems can be simplified by enforcing arc consistency. This library provides an implementation of the popular AC-3 algorithm as solver.State.MakeArcConsistent(). Call this method before calling solver.Solve() to achieve best results.
- See the Sudoku solver for an example of how to use arc consistency.

Project Status

Currently, this project is very much a work in progress. Here are some of its limitations:

Numeric comparison constraint (less than, greater than, etc.) generators are not yet supported, but are on the way. Variables currently use the Go interface{} type for their actual values, so equality and inequality are supported out of the box.
I have plans to implement the minimum remaining values (MRV) heuristic, the least constraining value (LCV) heuristic, and the degree heuristic.
Unit tests need to be written. It would also be nice to have some better documentation.

Examples

For example usage of this library, see the examples/ directory.

Documentation

Godocs are available here.

Installation

go get github.com/gnboorse/centipede

So far, this project has only been tested on macOS and Linux.

Contributing

Feel free to make a pull request if you spot anything out of order or want to improve the project.

Go is not my primary programming language, but I have been wanting to learn it for a while now. Feel free to fix anything that isn't idiomatic Go. I come from a Java/Python background.

darinpp/centipede